Critical analysis of Mediterranean sea level limit cycles during the Messinian salinity crisis
Baum, Mark M. (Department of Earth and Planetary Sciences, Harvard University)

Data:	2021
Resum:	The Messinian Salinity Crisis (5. 97-5. 33Ma) may be one of the most significant periods of sea-level change in recent geologic history. During this period, evaporite deposition throughout the Mediterranean basin records a series of dramatic environmental changes as flow through the Strait of Gibraltar was restricted. In the first stage of evaporite deposition, cycles of gypsum appear in shallow basins on the margins of the Mediterranean. The complex environmental history giving rise to these cycles has been investigated for decades but remains controversial. Notably, whether the evaporites are connected to significant changes in Mediterranean sea level is an open question. In one proposed model, competition between tectonic uplift and erosion at the Strait of Gibraltar gives rise to selfsustaining sea-level oscillations-limit cycles-which trigger evaporite deposition. Here I show that limit cycles are not a robust result of the proposed model and discuss how any oscillations produced by this model depend on an unrealistic formulation of a key model equation. First, I simplify the model equations and test whether limit cycles are produced in 64 million unique combinations of model parameters, finding oscillations in only 0. 2% of all simulations. Next, I examine the formulation of a critical model equation representing stream channel slope over the Strait of Gibraltar, concluding that a more realistic formulation would render sea-level limit cycles improbable, if not impossible, in the proposed model.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, fins i tot amb finalitats comercials, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria de l'obra original.
Llengua:	Català
Document:	Article ; recerca ; Versió publicada
Matèria:	Messinian salinity crisis ; Sea-level change ; Mediterranean ; Strait of gibraltar
Publicat a:	Geologica acta, Vol. 19 (2021) , p. 1-11 (Articles) , ISSN 1696-5728

Adreça original: https://raco.cat/index.php/GeologicaActa/article/view/391475
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/33997
DOI: 10.1344/GeologicaActa2021.19.10

11 p, 5.1 MB

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